Table 3. Membrane intactness and subtle changes in sperm membrane integrity of stallion spermatozoa stored during five days (day 1 D1 to day 5 D5) at 5°C FE fresh extended sperm, CC sperm processed through colloidal centrifugation.

	D1		D3		D5
	FE	CC	FE	CC	FE	CC
Intact%	58.1±12.9c	72.4±13.2a	51.3±9.9c	60.4±9.1c	45.8±11.7b	49.9±11.0b
YoPro+ %	12.7±6.7a	8.6±2.9a	9.4±2.7a	8.41±3.3a	20.7±18.9b	18.5±10.8b
YoPro+/Eth+ %	21.6±12.9	12.3±11.1	28.2±9.9	18.5±3.7	22.9±13.1	25.9±9.9
Eth+ %	7.5±6.2	6.6±7.0	11.0±8.6	12.8±6.2	10.5±10.3	5.5±4.6

Intact spermartozoa are those not stained and thus represent spermatozoa with completely intact membranes. YoPro+ are early apoptotic sperm depicting an increase in sperm membrane permeability, YoPro+/Eth+ are late apoptotic and Eth+ are necrotic spermatozoa. Within a row values with different superscript differ statistically a-c p<0.01. (means ± SD) Results are derived from 28 identical experiments (7 stallions, 4 ejaculates per stallion).